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February 2005, Week 4

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Subject:
From:
john pitman <[log in to unmask]>
Reply To:
john pitman <[log in to unmask]>
Date:
Tue, 1 Mar 2005 10:50:10 +1100
Content-Type:
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text/plain (88 lines)
If you are likely to do partial tests on a key value, why would you make it
a J2? Or part of a compound? Surely it would have to be a stand alone key?
The test you postulate is

Field_a = test1, field_b = test 2, Field_c modulo 100 = 34

Or if it's a char key, test on field_c is "????34" so your test would be 28
? in front of the size of the field_c number

I usually conceive of partial retrievals such that the known part is on the
left (ie high order) so I can start at partial+nulls, and run until I get
data the same length as partial is higher than partial. As soon as you have
partial NOT starting on left, you are pretty much in for a serial run,
unless you have inverted indexes to cope with that retrieval. Don't know if
ODX can do that for you?

jp

-----Original Message-----
From: Brian Donaldson [mailto:[log in to unmask]] 
Sent: Tuesday, 1 March 2005 10:02 AM
To: HP3000 List; John Pitman
Subject: Re: Omnidex Question

Let me clarify --

If I have an ODX key made up of 3 different fields, example:

ODX-key-1 made up of field-a (X8), field-b (X20) and field-c (J2)

my question would be -- Can you do a partial key retrieval on the J2 ?

If the values in the DB J2 field are +1234 would I be able to do a partial
key retrieval on the value +34 and get all the entries in the set
containing those values ?

You asked "Why would I?" Well, I wouldn't pay DISC thousands of dollars for
Omnidex so I could do Query serial reads to find the entries I am looking
for. :-)

I expect to get a big bang for my Omnidex buck....

Actually, the more I think about it, I don't think building an ODX key with
COMP fields in it is such a great idea after all...

Looks like I answered my own question.

Brian.

On Mon, 28 Feb 2005 14:44:13 +1100, john pitman <[log in to unmask]> wrote:

>WHAT WOULD THAT MEAN ?
>Wouldn't that be like (in query)
>Find key is between 1000,1999
>
>
>??Why would you??
>
>jp
>
>-----Original Message-----
>From: HP-3000 Systems Discussion [mailto:[log in to unmask]] On Behalf
>Of Brian Donaldson
>Sent: Monday, 28 February 2005 9:39 AM
>To: [log in to unmask]
>Subject: [HP3000-L] Omnidex Question
>
>It's been a while since I did anything with ODX...
>
>If I have an ODX key that is a COMP field (J1, J2, J4, P8, P16 etc)
>is it possible to do a partial key retrieval on the value in any of these
>types of keys?
>
>Or are these types of keys a no-no ??
>
>
>TIA,
>Brian Donaldson.
>
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